Substance B2M to Blender Workflow
Cynicat Pro really helped me out with explaining how you can connect the Substance bitmaps to his PBR node groups. 



In the material node group you may notice that :


when importing a DirectX normal map you have to convert it to Open GL normal map
the roughness is corrected with power node before connecting it to the shaders (according to JtheNinja" The other thing we need to do is square the roughness value to match the range between SP and Cycles. To do that, add a math node, set it to “power”, connect your roughness map to the top slot, and set the bottom slot to “2.0”."
the metallic map is a sort of mask that tells blender what is metallic and what is not


This seems a very elegant setup with little fuss and very reusable. Comments ?

Now I also learned that you can download compiled Substance files from Textures.com and open these in Substance Player (free) and tweek the maps before exporting the bitmaps. This next to importing images in B2M and creating your own bitmaps. Apart from some issues with the displacement map it seems to work fine